Nature Definition and 730 Threads

A new paper published recently in the Nature Communications journal suggests the AMOC will go through a tipping point by 2057. It is a controversial result that is being hotly debated in scientific circles. Wired magazine provides the backstory to the paper and the principal researchers...

I am nobody important, and don't have any relevant training. I do what I enjoy, and learn whatever my curiosity demands. Lately, that has involved taking a close look at the properties of fundamental particles, trying to see if I can identify any interesting patterns. There are a few! I hope to...

Been dipping my toes into maths by examining how equations work on the most basic level, and I love encountering equations that turn out to model similar aspects in nature, for example the inverse square law is apparent in equations for gravity and for electromagnetism. In the thumbnail of...

What is the main reason for a free field staying free according to Haag's theorem?

The editors of high impact journal Nature Physics explain why the field of quantum foundations is important for physics. https://www.nature.com/articles/s41567-022-01766-x

I have two doubts about the article Raman published in 1928 on Nature when he discovered Raman effect, precisely about these two sentences he wrote:1. What does it mean the modified scattering corresponds to their fluctuations in Compton effect? I think he's talking about the radiation...

Have you ever discovered any animals which as you read about their activities or life cycle, just seemed so horrific that their very nature almost felt like an argument against Divine Creation? If Satan had a zoo, what kinds of animals from this Earth do you think he would put in it?

Recent jailbreak of a robot vacuum from a Cambridge TraveLodge https://www.bbc.co.uk/news/uk-england-cambridgeshire-60084347

I was reading Six easy pieces from Feynman and I got stuck what is electromagnetism 2 years ago. Recently I came across a video and I think I have figured it out. The paragraph says like this: “ If we were to charge a body, say a comb, electrically, and then place a charged piece of paper at...

Hi! The problem clearly states that there is a surface charge density, which somehow gives rise to a potential. The author has solved the Laplace equation in cylindrical coordinates and applied the equation to the problem. So ##\nabla^2 V(r,\phi) = 0##, and ##V(a,\phi) = V_a(\phi)## (where...

Summary:: What does physics study? Other than matter/antimatter and energy what does physics study? And in what ways are matter and energy similar? Are there additional substances that physics measures?

I am just wondering how best to visualise a Compton scattering event. Since a photon has no mass, we can't exactly presume it's the same as two masses colliding even if at relativistic speeds. Does the photon encounter some kind of force field as it approaches the stationary electron ? If so...

I have found the turning point. I want to ask how to check the nature of the turning point. My idea is to change the equation into cartesian form then find the second derivative and put the ##x## value of the turning point. If second derivative is positive, then it is minimum and if the second...

They're dimensions, so they DO have a metric equation, right? Does energy flow cyclically between pairs of dimensions? To me, that's what rotation is.

Why are lights reflecting off horizontal surfaces like the road, water, or snow horizontally polarized? How does the process happen?

I would like to know, how can we be sure this is not due to the influence/impact/interference of our measurement, not necessarily the intrinsic nature of photons? In most reference books, it seems it is a given and it is not discussed

So initially I thought quantum mechanics was deterministic in the equations but was probabilistic in measurement. I’m aware of bell’s inequality which rules out hidden variables unless you assume super determinism. But recently I’ve come across something called decoherence and some people have...

I guess the first question is whether it is true that things in nature have a tendency to use good color combinations. It seems to me to be true, when it comes to animals, insects, and flowers, for example. Supposing this is true, how/why does nature choose aesthetic colors? Is there a...

In Anthony French's book, Newtonian Mechanics, while explaining the non-Euclidean nature of the 3-d space, he poses a problem (I have rephrased it slightly): Suppose you are on Earth's equator (r = 6,400 km) at the prime meridian (point I). You first walk along the equator 1000 miles east and...

Thanks to BBC for making it readable for a layman link to the article: https://www.bbc.com/news/56643677

The question about how using limits can give us the exact slope of a line tangent to a curve is something so far I haven't quite been able to grasp. I do intuitively understand how using limits can get us so close to the exact slope that any difference shouldn't matter in the real world because...

Genetic mechanisms of critical illness in Covid-19 33 pages. Free PDF download at: https://www.nature.com/articles/s41586-020-03065-y_reference.pdf "...we found evidence in support of a causal link from low expression of IFNAR2, and high expression of TYK2, to life-threatening disease...

How do I distinguish between a point of local maxima or minima, when the second derivative in that point is equal to zero?

Hey guys! I read this fascinating paper about the discovery of a white dwarf merger remnant: https://www.nature.com/articles/s41586-019-1216-1 To quote the abstract: "For white dwarfs, the mass of the merger product may exceed the Chandrasekhar limit, leading either to a thermonuclear explosion...

As I've stated many times before, I was a social science major in college, so this is not my thing. . .I ask, because I've seen it referred to that way by sources I cannot verify (random internet chat). Figured I could get quick answer here that is trustworthy. I also ask, because I'll...

By rearranging over and over ratio formulas involving frequency, speed and wavelength, I came up with the equation: fP/fQ=10^-8xVP/VQ This led me to take into account only rows A, B, E, and F... but I can't really understand which one of these is the right one.

Prove that the polynomial equation $x^8-x^7+x^2-x+15=0$ has no real solution.

Is it possible for new forces or fields of nature to be connected to quantum foundations? For example, new forces or fields that choose the decoherent histories or branches. Or generally actualize one of the decoherence branches? Or should new forces or fields of nature be reserved for...

I belong to an institution where they are subscribed to view the article contents in Nature Publications. I used to be able to download articles without problem but recently, I tried downloading a research article from Nature Physics, but the "Download PDF" option was missing, although the main...

Classical electromagnetic propagation evokes an electric field at right angles to a magnetic field. Does this complementary directionality have a simpler basis in QED? Are there any examples of an orthogonal component in other fundamental interactions? Thanks.

Hi. I am reading quantum optics by Marlan Scully currently. Although the book has devoted a whole section to explain the photon concept, I am still confused about some nature of photons. First, how do photons distribute in space? For example, there are ##n## photons for a Fock state ##\left | n...

I know that things like our fingerprint is generally unique and our face is generally unique, unless a twin but chances are rare. How about our voice? Is our unique in nature? Usually how frequent do two persons have the voice indistinguishable by computer or detector? If someone intentionally...

A gas of bosons or fermion particles follows a particular quantum statistics. Then why a molecular gas (say, H2) follows a classical distribution statistics? Is it not the case that the molecules should be indistinguishable one from another and be either bosons or fermions? What is exactly the...

Moderator's note: Spun off from another thread due to topic change. Isn't Dark Energy a continuous creation theory?

Formal logic can be studied from the viewpoint of rules for deriving strings of symbols from other strings of symbols. Computability can be studied from the viewpoint of a machine operating on a 1 dimensional tape. It seems that, in math, we can handle computation and deduction in two...

Posted on more pseudescience related sites is a story about, a group that claim to have discovered evidence of a new force of nature, with a claimed sigma of 7,7. The arxiv paper have not yet been peer-reviewed, so I am not sure if it is allowed. If not I am sorry, and will understand. I am...

How was it discovered that electromagnetic radiation is electromagnetic? -- Jeff, in Minneapolis

I'm a high school teacher. In the curriculum, students are required to explain that polarization of light shows that light is a transverse wave. My answer: In order to explain polarization, we have to consider the electric field vibration direction. For example, on a wave that propagates...

In quantum electrodynamics, the energy exchange between two charged particles is called a virtual photon, allowing the exchange of quanta of energy between the two charged particles. But these are not the traditional photons of electromagnetic waves. They apparently just arise from the equations...

At the risk of sounding stupid, this question has always perplexed me. Einstein theorized that mass can not travel faster than the speed of light. I don't really understand it, I assume it has something to do with mass just being energy. Anyway imagine two objects in orbit of something with...

As a non-Physics major, like many others, I read science-fiction, hard science-fiction, have undergraduate/graduate courses on Astronomy and college physics. I also participated in R&D that produced electric rockets able to power small space vehicles (very slowly, but surely). I deal with...

In his book, "The greatest story ever told", Lawrence Krauss states: "Gauge invariance ... completely determines the nature of electromagnetism." My question is simple: How? I have gone back thru the math. Gauge invariance allows us to use the Lorenz gauge with the vector and scalar potentials...

Hello. Wannabe sci-fi writer here with what may be a simpleton's question. From Google et al: "It took 380,000 years for electrons to be trapped in orbits around nuclei, forming the first atoms. These were mainly helium and hydrogen, which are still by far the most abundant elements in the...

We have been taught that the there is no experiment designed to detect wave and particle nature of light simultaneously. Also, that light propagates by the virtue of its wave nature and interacts by the virtue of its particle nature. let us take an electron beam passing through two slits...

Summary: The Space Between the Nucleus and Electron Shells? What composes the space between an atom's nucleus and its electron shells?

I was reading another thread which has been closed, so I cannot ask this question there. The question is about a post by @PeterDonis (post #21). https://www.physicsforums.com/threads/what-happens-to-the-inertia-of-a-mass-falling-into-a-black-hole.970627/ There are no internal pressures inside a...

Basically as the title says. I'm interested in the naturally occurring EM waves, and I would like to know the strongest EM waves out there. I'm not talking about "strong" as in energy per photon that is proportional to the frequency, but about the overall energy transported by the wave that is...

Since light intensity is proportional to the amplitude of the EM wave, and wave amplitudes undulate up and down, does this result in natural intensity flickering of observed light? For visible light, the frequency is extremely high, but it might be more easily observable in ELF waves.

I just saw this public lecture and I really enjoyed it (the lecture begins at about 18 minutes into the video). He is an engaging and rather funny speaker. At the end there is a Q&A in which he for instance goes into some of the misconceptions about quantum mechanics. David Kaplan is also one of...

Why are photoelectric measurements sensitive to the nature of the photoelectric surface?